Heat sink



FIG. 1 is a perspective view of a first heat sink of the present design;

FIG. 2 is a bottom view of the heat sink of FIG. 1;

FIG. 3 is a top view of the heat sink of FIG. 1;

FIG. 4 is a right side view of the heat sink of FIG. 1, the left sideview of the heat sink of FIG. 1 being a mirror image thereof;

FIG. 5 is a front view of the heat sink of FIG. 1, the rear view of theheat sink of FIG. 1 being identical thereto;

FIG. 6 is a perspective view of a second heat sink of the presentdesign;

FIG. 7 is a bottom view of the heat sink of FIG. 6;

FIG. 8 is a top view of the heat sink of FIG. 6;

FIG. 9 is a right side view of the heat sink of FIG. 6, the left sideview of the heat sink of FIG. 6 being a mirror image thereof; and,

FIG. 10 is a front view of the heat sink of FIG. 6, the rear view of theheat sink of FIG. 6 being identical thereto.

Any parts shown in broken lines form no part of the claimed design.

The ornamental design for a heat sink, as shown and described.